William did 18 more sit-ups than Umaima around noon. William did 43 sit-ups. How many sit-ups did Umaima do?
Solution: William did 43 sit-ups, and Umaima did 18 fewer than that, so find the difference. The difference is $43 - 18$ sit-ups. He did $43 - 18 = 25$ sit-ups.